She was cast for a sitcom on The CW directed by Amy Sherman-Palladino, tentatively titled "Wyoming", but only a pilot was produced since the project was not picked up by the network.

She was then cast to appear as Nell Jones on NCIS: Los Angeles. Initially only planned to be a recurring character, Smith's role was expanded to main character status after impressing the producers with her acting.[3] In 2011, she appeared as a supporting character in Detachment.